Vacuum insulating glass (VIG or vacuum IG) units are known in the art. FIG. 1 is a conventional vacuum IG unit 100. VIG unit 100 includes two spaced apart glass substrates 102 and 104, which enclose an evacuated or low pressure space 110 therebetween. Glass sheets/substrates 102 and 104 are interconnected by peripheral or edge seal of fused solder glass 108 and an array of support pillars or spacers 106.
A pump-out tube is hermetically sealed by solder glass to an aperture or hole, which passes from an interior surface of glass sheet 102 to the bottom of recess 114 in the exterior face of sheet 104. A vacuum is attached to pump-out tube so that the interior cavity between substrates 102 and 104 can be evacuated to create a low pressure area or space 110. After evacuation, the tube is melted to seal the vacuum, forming cover 112. The recess 114 retains the sealed tube. Optionally, a chemical getter may be included within the recess 114.
Unfortunately, vacuum insulating glass units tend to be fragile. For example, they are susceptible to damage from shocks and/or strikes. This may lead to breakage of one or both of the substrates, at least partial separation of the solder 108, degradations in the insulating performance of the unit as a whole, and/or the like. Vibrations also may adversely affect the VIG unit. Although conventional insulating glass units tend to be more robust as compared to VIG units, such conventional IG units generally do not provide the same high levels of insulating features of VIG units.
Thus, it will be appreciated that there is a need in the art for vacuum insulating glass units having increased resiliency and/or improved insulating features.
In certain example embodiments of this invention, a window unit is provided. Four substantially parallel spaced-apart glass substrates are arranged so as to form a center gap between the two inner substrates and first and second outer gaps respectively between each of the two inner substrates and the two outer substrates. At least one spacer element is provided proximate to each end of a major axis of the window unit so as to maintain the four substrates in substantially parallel-apart relation to one another. A sealant is provided at least adjacent to the at least one spacer element at each end of the major axis of the window unit so as to at least partially seal the window unit. The center gap between the two inner substrates is provided at an inner gap pressure, the inner gap pressure being a pressure below atmospheric. The first and second outer gaps are provided at pressures greater than the inner gap pressure. The window unit has an R-value of at least about 11 measured at a center thereof.
In certain example embodiments, a window unit is provided. A vacuum insulating glass unit is provided. First and second glass substrates are located on opposing sides of the vacuum insulating glass unit so as to form first and second outer gaps between the first substrate and the vacuum insulating glass unit and between the vacuum insulating glass unit and the second substrate, respectively. At least one spacer element is provided proximate to each end of the vacuum insulating glass unit so as to maintain the first and second glass substrates and the vacuum insulating glass unit in substantially parallel-apart relation to one another. A sealant is provided at least adjacent to the at least one spacer element at each end of the major axis of the vacuum insulating glass unit so as to at least partially seal the window unit. The vacuum insulating glass unit includes an inner air gap at an inner gap pressure, the inner gap pressure being a pressure below atmospheric. The first and second outer gaps are provided at pressures greater than the inner gap pressure. The window unit has an R-value of at least about 11 measured at a center thereof.
In certain example embodiments, a method of making a window unit is provided. Four substantially parallel spaced-apart glass substrates are provided so as to form a center gap between the two inner substrates and first and second outer gaps respectively between each of the two inner substrates and the two outer substrates. At least one spacer element is provided proximate to each end of a major axis of the window unit so as to maintain the four substrates in substantially parallel-apart relation to one another. A sealant is provided at least adjacent to the at least one spacer element at each end of the major axis of the window unit so as to at least partially seal the window unit. The center gap between the two inner substrates is provided at an inner gap pressure, the inner gap pressure being a pressure below atmospheric. The first and second outer gaps are provided at pressures greater than the inner gap pressure. The window unit has an R-value of at least about 11 measured at a center thereof.
In certain non-limiting implementations, the spacer may be substantially U-shaped, whereas two pillar-like spacers may be used in connection with certain other non-limiting implementations. The at least one spacer element may be a butyl-based spacer element, a foam-based spacer element, a warm-edge spacer element, etc., in certain non-limiting implementations. In certain non-limiting implementations, the sealant may be a polysulfide based sealant, a one- or two-part silicone based sealant, a polyurethane based sealant, a dual seal equivalent sealant product, a hot melt butyl based sealant product, etc.
The features, aspects, advantages, and example embodiments described herein may be combined to realize yet further embodiments.